Re: database design method

> >With user defined types, one can define whatever type one wants.
>
> That depends upon what the minimal requirements are for defining it. If I
> have to define a function that outputs the representation of the value then
> there is a problem. It also depends on how exactly you can denote or create
> new values. As long as these things are not exactly specified it is not
> clear if you can use abstract identifiers or not.
>

Is there a theoretical problem with just using plain
integers as surrogates or "object id's"? Or is it just that we
want to prevent the user from comparing apples and oranges?